High-speed networks are continually evolving. The evolution includes a continuing advancement in the operational speed of the networks. The network implementation of choice that has emerged is Ethernet networks physically connected over unshielded twisted pair wiring. Ethernet in its 10/100/1000/10G BASE-T form is one of the most prevalent high speed LANs (local area network) for providing connectivity between personal computers, workstations and servers.
FIG. 1 shows a block diagram of a pair of Ethernet transceivers communicating over a bi-directional transmission channel, according to the prior art. An exemplary transmission channel includes four pairs of copper wire 112, 114, 116, 118. The transceiver pair can be referred to as link partners, and includes a first Ethernet port 100 and a second Ethernet port 105. Both of the Ethernet ports 100, 105 include four transmitter TX, receiver RX, and I/O buffering sections corresponding to each of the pairs of copper wires 112, 114, 116, 118.
High speed Ethernet networks (including, for example, the Ethernet transceivers of FIG. 1) support full-duplex transmission in a single frequency band. Ethernet transceivers typically co-exist with many other communication systems as well as other Ethernet transceivers. These Ethernet transceivers use a very wide transmission bandwidth and can therefore interfere with other communication systems. Moreover, electromagnetic capacitive and inductive coupling are often much stronger at higher frequencies so that the interference coupling becomes stronger with higher frequencies.
In many Ethernet system deployments, many transceivers are placed close together to achieve cable bundling to efficiently pack and route the Ethernet cables in the plant. Such bundling results in the cables being physically very close to each other and so the cables' receivers suffer from increased interference. Such cross-talk energy coupling appears as an additional distortion source for each receiver and results in worst link margin, performance, and error rate.
Prior approaches are often passive, meaning that they take no action to combat this additional cross-talk distortion and therefore suffered the performance degradation or reduced margin of the system.
Better materials, such as better cable shielding can help reduce the effects of cross-talk. Also, better design of the boards where multiple transceivers reside can also help reduce the effects of cross-talk. Such design can involve the placement and routing of wires and traces that result, for example, in reduced onboard coupling. Similarly, the cables conducting the transmitted information could be designed with better shielding and twisting to reduce the crosstalk that the travelling signals generate. Similarly, the board and package components can be made from higher quality materials resulting in improved cross-talk rejection.
Such approaches are not always possible because of other constraints such as material cost, area, legacy structure, power, and other constraints.
It is desirable to have an apparatus, method, and system for mitigating cross-talk of Ethernet systems that do not require any additional materials and cost, and are compatible with all possible current and future deployments.